TY - JOUR T1 - Thioether Metabolites of 3,4-Methylenedioxyamphetamine and 3,4-Methylenedioxymethamphetamine Inhibit Human Serotonin Transporter (hSERT) Function and Simultaneously Stimulate Dopamine Uptake into hSERT-Expressing SK-N-MC Cells JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 298 LP - 306 DO - 10.1124/jpet.104.069260 VL - 311 IS - 1 AU - Douglas C. Jones AU - Serrine S. Lau AU - Terrence J. Monks Y1 - 2004/10/01 UR - http://jpet.aspetjournals.org/content/311/1/298.abstract N2 - 3,4-Methylenedioxyamphetamine (MDA) and 3,4-methyl-enedioxymethamphetamine (MDMA, ecstasy) are widely abused amphetamine derivatives that target the serotonin system. The serotonergic neurotoxicity of MDA and MDMA seems dependent on their systemic metabolism. 5-(Glutathion-S-yl)-α-methyldopamine [5-(GSyl)-α-MeDA] and 2,5-bis(glutathion-S-yl)-α-methyldopamine [2,5-bis(GSyl)-α-MeDA], metabolites of MDA and MDMA, are also selective serotonergic neurotoxicants and produce behavioral and neurochemical changes similar to those seen with MDA and MDMA. We now show that 5-(GSyl)-α-MeDA and 2,5-bis(GSyl)-α-MeDA are more potent than MDA and MDMA (Ki = 69, 50, 107, and 102 μM, respectively) at inhibiting 5-hy-droxytryptamine (serotonin) transport into SK-N-MC cells transiently transfected with the human serotonin transporter (hSERT). Moreover, 5-(GSyl)-α-MeDA and 2,5-bis(GSyl)-α-MeDA simultaneously stimulated dopamine (DA) transport into the hSERT-expressing cells, an effect attenuated by fluoxetine, indicating that stimulated DA transport was hSERT-dependent. Finally, 5-(GSyl)-α-MeDA and 2,5-bis(GSyl)-α-MeDA, and to a lesser extent MDA and MDMA, induced a concentration and time-dependent increase in reactive oxygen species (ROS) in both hSERT and human dopamine transporter-transfected cells. Fluoxetine attenuated the increase in ROS generation in hSERT-expressing cells. The results are consistent with the view that the serotonergic neurotoxicity of MDA and MDMA may be mediated by the metabolism-dependent stimulation of DA transport into hSERT-expressing cells and ROS generation by redox active catechol-thioether metabolites and DA. The American Society for Pharmacology and Experimental Therapeutics ER -